The invention generally relates to curable compositions including cyanate ester resins. More particularly, the invention relates to cyanate ester resin compositions for bonding of an article, such as, the windings or core laminates of an electrical machine.
The stator windings of electrical inductive devices, such as motors, are typically wound with magnet wire having an enamel, or other insulative coating thereon. However, it may be desirable to further coat the windings and seal them from the environment, using varnish compositions, for example. Conventional varnish compositions typically have a glass transition temperature (Tg) below 80° C. and poor thermal stability. As a result, their performance at operating temperature, is unsatisfactory and may result in significant thermal degradation even after short operating times. In addition, these varnish compositions are brittle, and subject to cracking, particularly when subjected to vibrations.
Thus, improved varnish compositions for bonding windings or core laminates in an electrical machine are desired. Further, improved methods for bonding windings or core laminates in an electrical machine are also desired.